Knee Anatomy 101

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Knee replacement has become a relatively commonplace procedure — last year in the U.S. over 700,000 people had knee replacement. Those numbers are expected to continue to grow as more and more baby boomers move into their mid to upper 60s and above. Estimates place knee replacements in the U.S. at 3.5 million by 2030. 

That’s a whole lotta titanium and Teflon replacing bone and cartilage. 

Dr. Moore is a board-certified orthopaedic surgeon who has been serving our patients at Pinehurst Surgical for over two decades, and he has helped many people overcome their chronic knee pain caused by osteoarthritis through outpatient and inpatient knee replacement. 

But what do we all really know about our knees anyway? We know they allow us to make all sorts of complex movements, from running in a softball game to springing up to grab a rebound on a basketball court. But what makes up our knees? Let’s get into that in this autumnal blog for Pinehurst Surgical Orthopaedic & Joint Replacement. 

Let’s call it Knee 101. 

The largest joint in the body 

Working like a hinge, our knee is the largest joint in the human body. It’s the junction of the bones of the upper and lower legs. The knee consists of three bones: the femur (thigh bone), the tibia (shin bone), and the patella (the kneecap). 

The ends of the bones are covered with a layer of cartilage, a slick, elastic material that absorbs shock and allows the bones to glide easily against one another as they move. Between the tibia and femur bones are two crescent-shaped pads of cartilage that reduce friction and disperse the weight of the body across the joint. They are the lateral meniscus (situated at the outside of the knee) and the medial meniscus (situated on the inside of the knee). 

The bones of the knee are held together in a joint capsule, which consists of two distinct layers — an outer layer of dense connective tissue and an inner membrane, called the synovium, which secretes a fluid to lubricate the joint. 

The outer layer of the capsule is attached to the ends of the bones and is supported by these ligaments and tendons: 

  •     Quadriceps tendon, which attaches the quadriceps to the patella
  •     Medial collateral ligament (MCL), which gives stability to the inner part of the knee
  •     Lateral collateral ligament (LCL), which stabilizes the outer part of the knee
  •     Anterior cruciate ligament (ACL), which is located in the center of the knee and prevents excessive forward movement of the tibia
  •     Posterior cruciate ligament (PCL), which is located in the center of the knee and prevents excessive backward shifting of the knee

Two groups of muscles support the knee: the hamstrings on the back of the thigh, which run from the hip to just below the knee and work to bend the knee; and the quadriceps, four muscles on the front of the thigh that run from the hip to the knee and straighten the knee from a bent position. 

Now you’re a knee expert. There’ll be a pop quiz later! So how does your knee feel? If it’s causing you chronic pain, it’s time to give us a call at Pinehurst Surgical, (910) 295-0224, and let’s see how Dr. Moore and our entire team can help.